The present invention relates to a percussion device of the type that is included in rock drilling machines.
In a previously known percussion device of this kind, see U.S. Pat. No. 5,372,196, it has been proved to be difficult to obtain sufficiently fast valve change-over in order to work at the high frequencies that are desired in modern high performance drilling. It is the primary object of the present invention to provide an improved percussion device increasing the speed of the valve change-over.